The present invention relates generally to hearing systems, devices, output transducer supports, and methods. More particularly, the present invention is directed to hearing systems that comprise an elongate support adapted to minimize contact with the ear while the transducer is positioned near the user's eardrum, thereby providing improved comfort to the user. The systems may be used to enhance the hearing process of those that have normal or impaired hearing with comfort.
People who wear hearing aids would like hearing aids with certain characteristics, such as cosmetic appeal, comfort and sound quality. With respect to comfort, hearing aids are often used for prolonged periods of time and people generally do not want to use a device that is uncomfortable. Although the importance of cosmetics will vary among individuals, people generally have a desire to hide a handicap such as a hearing deficit. Amplified sound quality is also important, in particular restoring the ears natural ability to detect sound localization cues at high frequencies. Although current hearing aids provide some benefit to the user, the above characteristics are generally not all satisfied with a single device.
Efforts to improve hearing aids have often resulted in an improvement of one characteristic at the expense of another. Early hearing aids included behind the ear hearing aides (hereinafter “BTE aids”) that placed much of the hearing aid electronics, for example the microphone and speaker, behind the ear. Although BTE aides provided somewhat improved hearing, these aids were readily apparent on the user and not cosmetically attractive. Advancements in electronics technology provided smaller components that led to the development of the completely in canal hearing aid (hereinafter “CIC aids”). The CIC aids have desirable cosmetics because the device is generally deep in the canal and not visible. However, these devices can be uncomfortable due to jaw movements, and the user's own voice can sound hollow and unnatural.
The unnatural and hollow sound that can occur with CIC aids has been referred to the occlusion effect. To reduce the occlusion effect, a vent can be placed in the CIC device that allows sound waves to pass through the device. Although such vents can improve the sound quality of the user's own voice, vents can also cause unwanted feedback, which produces a whistling sound.
A potential problem with hearing aids that place the microphone behind the pinna of the ear is that directionally dependent sound localization cues, for example in the 6 to 12 kHz frequency range, may not be present in the amplified signal. As described in the co-pending U.S. patent application Ser. No. 11/121,517, filed May 3, 2005, entitled “Hearing System Having Improved High Frequency Response”, these localization cues are important for understanding speech, for example speech of a desired person in the presence of additional people who are also speaking. Although placing the microphone near the ear canal can improve these sound localization cues, the microphone is often near a sound emitting transducer, such as a speaker, so that feedback can result.
Although open canal hearing aids can provide improved comfort, these devices have generally been deficient with respect to other desired characteristics. For example, some open canal hearing aids use external electronics, for example microphones and speakers such that these devices may not be cosmetically appealing. Also, open canal hearing aids have generally had limited success in providing frequency dependent sound localization cues. Open canal hearing aids are described in U.S. Pat. No. 5,987,146 and have been sold under the name of ReSound AiR, available from GN ReSound North America, Bloomington, Minn. Several modifications and refinements have been made to the original open canal hearing aids, for example as described in U.S. Pat. No. 5,606,621 and U.S. Pub. Nos. US 2005/0078843 and 2005/0190939, and open canal hearing aids are commercially available, for example from Vivatone Hearing Systems LLC of Shelton Conn.
Hearing aids with the sound sensitive microphone positioned in the ear canal show some promise of potentially providing sound localization cues. However, placement of the microphone in the canal of an acoustic hearing aid which uses a sound generating speaker positioned in the ear canal can produce significant feedback. Thus, many open canal acoustic hearing aids do not use a microphone in the ear canal. Although the amplification gain of a hearing aid device can be decreased to reduce feedback, decreasing the gain can also make it harder for a user to hear weak sounds, which is contrary to the purpose of wearing a hearing aid device. Because of this feedback that generally precludes placement of the microphone in the ear canal, many acoustic hearing aids do not provide directionally dependent sound localization cues. One approach to providing sound localization cues has been to provide a directional microphone instead of an omni-directional microphone. However in at least some instances, devices using directional microphones have met with only limited success.
One promising approach to provide sound localization cues has been to place the microphone inside the ear canal and drive the eardrum or other ear structure directly with non-acoustic energy, for example with electromagnetic energy, so that feedback is reduced. Rather than using acoustic energy to drive the eardrum, the eardrum can be driven electromagnetically with a magnet placed on the ear so as to reduce the acoustic feedback to the ear canal microphone as discussed in U.S. Pat. Nos. 5,259,032; 5,276,910; and 5,425,104; as well as U.S. patent application Ser. No. 11/121,517 and U.S. Patent Application Publication No. 2006/0023908, entitled “Transducer for Electromagnetic Hearing Devices”. Such devices typically use a coil wrapped around a core (hereinafter “core/coil”) to transmit electromagnetic energy from the coil to the magnet positioned on the ear structure.
One difficulty encountered with hearing aid devices that use a coil to electromagnetically drive a magnet positioned on the eardrum, stapes or other ear structure is that such devices can be uncomfortable for the user. Work in relation with the present invention suggests that this discomfort is associated with placement of the coil deep within the ear canal near the eardrum. One the one hand, this placement near the eardrum is desirable as the coil is near the magnet positioned on the ear structure so that electromagnetic energy can be effectively coupled to the magnet. However, as the coil is positioned near the eardrum, the coil should be held accurately to avoid damage to the eardrum. With such devices, an ear canal shell can be used to hold the core/coil in place deep within the ear canal. Although the shell can be customized specific to each user, for example molded, and have openings to provide an open canal hearing aid design, such devices have provided less than ideal results. In particular, users can experience skin irritation, discomfort, and even ear pain due to friction between the shell and the canal skin. Friction can arise from speech production, mastication, and swallowing, potentially causing irritation and discomfort.
In addition to the shortcomings described above, present coil designs for electromagnetically driven eardrum magnet hearing aids may be less than ideal. In some instance, the size requirements of the coil are dictated by electromagnetic field requirements (B fields) to drive the magnet. However, the size of the coil of such devices may be larger than necessary and contribute to user discomfort.
In light of the above, what is needed is a comfortable hearing aid device that is cosmetically attractive and provides good sound quality including sound localization cues.
Description of the Background Art. U.S. Pat. Nos. 5,259,032; 5,276,910; 5,425,104; 5,987,146 and 5,606,621 have been described above. Other patents of interest include: U.S. Pat. Nos. 4,800,084; 5,804,109; 6,084,975 and 6,436,028. Patent Application Publication Nos. 2005/0078843; 2005/0190939 and 2006/0023908 have been described above. World Intellectual Property Organization (hereinafter “WIPO”) publication WO/2006/042298 is of interest. Journal publications of interest include: Hammershoi and Moller, “Sound transmission to and within the human ear canal,” J. Acoust. Soc. Am., 100(1):408-427; Decraemer et al., “A method for determining three-dimensional vibration in the ear,” Hearing Res., 77:19-37 (1994); Puria et al., “Sound-pressure measurements in the cochlear vestibule of human cadaver ears,” J. Acoust. Soc. Am., 101(5):2754-2770 (May 1997); Moore, “Loudness perception and intensity resolution,” Cochlear Hearing Loss, Chapter 4, pp. 90-115, Whurr Publishers Ltd., London (1998); Puria and Allen “Measurements and model of the cat middle ear: Evidence of tympanic membrane acoustic delay,” J. Acoust. Soc. Am., 104(6):3463-3481 (December 1998); Hoffman et al. (1998); Fay et al., “The discordant eardrum,” Proc. Nat. Academ. Sci. USA 103(52):1974-8 (2006); and Hato et al., “Three-dimensional stapes footplate motion in human temporal bones,” Audiol. Neurootol., 8:140-152 (Jan. 30, 2003). Conference presentation abstracts from the Association for Research in Otolaryngology: Best et al., “The influence of high frequencies on speech localization,” Abstract 981 (Feb. 24, 2003); and Carlile and Schonstein, “Frequency bandwidth and multi-talker environment,” Aud. Eng. Soc. (2006).